#include<stdio.h>

int search(int arr[], int left, int right, int sum)
{
	int mid = 0;
	while (left <= right)
	{
		mid = (left + right)/2;
		if (arr[mid] < sum)
			left = mid + 1;
		else if (arr[mid] > sum)
			right = mid - 1;
		else
			return mid;
	}
}
int main()
{
	int arr[] = { 0,1,2,3,4,5,6,7,8,9 };
	int left = 0;
	int right = sizeof(arr) / sizeof(arr[0]) - 1;
	int sum = 5;
	int s;
	s = search(arr, left, right, sum);
	printf("%d", s);
	return 0;
}
